1. Field of the Invention
The invention concerns a transverse flux machine with conductor rings and u-shaped soft magnetic bodies.
2. Description of the Prior Art
A transverse flux machine is impressive because of the simplicity of its winding. On the other hand, the production of the soft magnetic body incurs considerably higher costs.
Material costs are increased by the waste incurred in punching the electric sheets, tool costs are increased by large and complicated dies, and assembly costs are increased by the handling of heavy component parts. The attainable efficiency and/or the power density of the machine are limited due to the saturation flux density of the soft magnetic material and the utilization factor of the air gap surfaces.
In DE 42 23 831 A1, a transverse flux machine is described which shows four winding rings of which two each have different diameters. The rotor elements are inserted axially into the four ring grooves of the stator resulting in a machine with eight air gaps in which the magnetic flux flows in radial direction.
From GB-PS 1 363 979, a transverse flux machine is known in which the rotors are arranged axially between the stators. The stators contain the conductor rings and in each magnetic circuit exist two air gaps with different radii.
From DE-PS 597 597, a single-phase transverse flux machine is known whose u-shaped soft magnetic cores are composed of two parts which are arranged around the conductor ring. The air gaps are located radially within the conductor ring and the dynamic effect of the magnetic field shows the same radial direction in all air gaps. The pulsating radial air gap forces act on the annular rotor housing and generate vibrations, noise, and losses. Therefore, the housing must be of solid and heavy construction.
Also, in the external rotor design known from DE 43 14 513 A1, the magnetic forces of the two air gaps of a magnetic circuit acting vertically with regard to the direction of movement are additive, thereby failing to achieve the objective of maximum power density.
GB 2 161 992 A describes a motor which provides rotary actuation in one direction only and which has u-shaped stator cores consisting of three parts. The piece parts which conduct the magnetic flux of the two phases are separated by a spacer. The magnetic forces acting radially in the air gap are additive.
From DE 43 14 513 A1, external rotor designs of transverse flux machines are known in which the magnetic flux radially within the magnetically active rotor elements flows through the air gap in radial direction. Power density is to be increased by more than 2 air gaps on both sides of the winding arrangement. This air gap arrangement permits the axial sliding into each other of rotor and stator at any time.
Numerous other designs of transverse flux machines are known which, however, utilize the soft magnetic material used only insufficiently and, in terms of production engineering, require costly sheet steel stamping.
The objective of the present invention is, therefore, to advance a transverse flux machine in such a manner that high efficiency and power densities are achieved with lowest possible production expenditures.